Super Duper Cool: BeOS 5 Pro on CD for less than $20!Not only did I find that Purplus still has BeOS Pro, but right now they have an excellent deal on it:
• $17.56 For the CD (No Manuals)
• For both PowerPC and Intel (note: won't work on PowerPC machines G3 or newer)
• Free shipping on orders over $15 (so you get it USPS Priority mail for free!)
You can check it out [here]

If you really want a manual, [The BeOS Bible by Scott Hacker] is better than anything Be provided, and in fact for a while The BeOS Bible and BeOS were bundled together.
Get it while you can! BeOS is still the most cutting edge, well thought out piece of software around.